Given a theme_location parameter, the function displays the menu assigned to that location. If no such location exists or no menu is assigned to it, the parameter fallback_cb will determine what is displayed.

If not given a theme_location parameter, the function displays

the menu matching the ID, slug, or name given by the menu parameter;

otherwise, the first non-empty menu;

otherwise (or if the menu given by menu is empty), output of the function given by the fallback_cb parameter (wp_page_menu(), by default);

.current-menu-parent
This class is added to menu items that correspond to the hierarchical parent of the currently rendered page.

.current-{object}-parent
This class is added to menu items that correspond to the hierachical parent of the currently rendered object, where {object} corresponds to the the value used for .menu-item-object-{object}.

.current-{type}-parent
This class is added to menu items that correspond to the hierachical parent of the currently rendered type, where {type} corresponds to the the value used for .menu-item-type-{type}.

.current-menu-ancestor
This class is added to menu items that correspond to a hierarchical ancestor of the currently rendered page.

.current-{object}-ancestor
This class is added to menu items that correspond to a hierachical ancestor of the currently rendered object, where {object} corresponds to the the value used for .menu-item-object-{object}.

.current-{type}-ancestor
This class is added to menu items that correspond to a hierachical ancestor of the currently rendered type, where {type} corresponds to the the value used for .menu-item-type-{type}.

This example will remove the unordered list wrap around the list items. Replacing the wrap HTML with the %3$s specifier results in only outputting the HTML list content for the menu items, because items_wrap is built using sprintf()

This example will allows you to add the word of your choice to the beginning of your menu as a list item. In this example, the word “Menu:” is added at the beginning. You may want to set an id on the list item (“item-id” in this example) so that you can use CSS to style it.